A randomized trial adapting contingency management targets based on initial abstinence status of cocaine-dependent patients

Objective: Contingency management (CM) reduces drug use, but questions remain regarding optimal targets and magnitudes of reinforcement. We evaluated the efficacy of CM reinforcing attendance in patients who initiated treatment with cocaine-negative samples, and of higher magnitude abstinence-based CM in patients who began treatment positive.

Method: Initially cocaine-negative patients (n = 333) were randomized to standard care (SC), SC + CM reinforcing submission of negative samples with $250 in prizes ($250Abs), or SC + CM reinforcing attendance ($250Att). Initially cocaine-positive patients (n = 109) were randomized to SC, $250Abs, or higher magnitude CM ($560Abs).

Results: For initially cocaine-negative patients, $250Abs and $250Att were equally efficacious to SC in enhancing longest duration of abstinence (LDA); $250Att patients submitted lower proportions of negative samples when missing samples were considered missing, but these patients also attended more study sessions, provided more samples, and submitted a higher proportion of negative samples than SC patients when expected samples were analyzed, ps < .05. In initially cocaine-positive patients, both CM conditions increased proportions of negative samples relative to SC when missing samples were excluded from analyses, but only $560Abs was efficacious in increasing LDA and proportion of negative samples when expected samples were analyzed, ps < .05. Follow-ups revealed no differences among groups, but LDA was consistently associated with abstinence during follow-up, p < .05.

Conclusions: High magnitude abstinence-based reinforcement improved all abstinence outcomes in patients who began treatment while using cocaine. For patients initiating treatment abstinent, both attendance- and abstinence-based CM resulted in improvements on some measures.